Composite article



v()ct. 3l, 1944.

J. F. MCWHORTER ETAL COMPOS ITE ARTICLE Filed Marcn`5,v1942 MN www www Rh NQ INVENTORS JHN E /Wc WHGRTEE BY M42/0N M HUMPHEEYS jwm ,Lf Sr .-\TTOR1 EY5 .W7/JW Patented Oct. 31, 1944 UNITED Y STATES X PATENT OFFICE A2,361,555, ,i Y COMPOSITE ARTICLE; l j John McWhorter, Cleveland.lfIe-iglits,v and Marion W. Humphreys, Euclid, Ohio,k assigncrs l to The Ohio Rubber Company, Willoughby, Ohio, a corporation of Ohio Application March 5, 1942, Serialro.V4-33,428

2 Claims.

This invention relates to the manufacture of refrigerator lids or other composite articles of the kind in which insulating material is encased in vulcanized soft rubber, and aims to provide an improved construction for such a composite article.

Our construction involves an improved method of producing it but the same is not claimed herein but in a divisional application Serial No. 478,370, filed March 8, 1943.

To produce a refrigerator lid or other composite article in which a body of insulating material is encasedin soft rubber vulcanized in place has presented a problem because the insulating material invariably contains moisture and air and may also contin some gas-evolving ingredients and when the insulating material is subjected to heat during the vulcanizing operation, the moisture is converted into steam 'and the air or other gas is expanded. This steam or other gaseous medium is trapped in theinsulating material by the rubber being molded and vulcanized around it and under the expansive effect of the in vulcanized rubber.

Other objects and advantages ofour inventionwill be apparent from the following description Awhen taken in conjunction with'the accompanying sheet of drawings, in which:

Fig. 1 is a bottom plan view of a composite refrigerator lid produced according to our invention;

Fig. 2 is a sectional view taken through the lid on line 2-2 of Fig. 1;

Fig. 3 is a partial transverse sectional View -taken through the lid on a larger scale to fur ther illustrate the construction; and

Fig. 4 is a transverse sectional viewv taken through molding apparatus which may be employed in carrying out our invention. n

More detailed reference will nowr be made to the drawing in which we have shown our irnproved refrigerator lid and the molding apparatus which may be used in producing the improved lid. Our method for producing composite articles will 'be hereinafter described in detail fill With reference being made-to such refrigerator lid and molding apparatus.

In Figs. 1 and -2 we show our refrigerator lid Illas comprising insulating material II encased in vulcanized soft rubber' I2. The lid may be of any desired shape or size and is here shown in the form of a disk provided with a handle I3 and having a tapered rim or periphery I 4 with an annular flange I5 projecting beyond such tapered rim. The insulated rubber-covered lid Ill may be used as a lid or cover for what is known as a deep-freeze unit or Withany 'other desired form of refrigerating apparatus. y

The insulating material II may be` any appropriate kind of insulating material such as a comminuted or brous substance which does not readily transmit heat or cold. For this insulating material we prefer to use a disk or slab of brousinsulating material of the kind known as Celotex. The slab maybe of a size, shape, and thickness appropriate to the use to be `made of the lid in which the slab is embodied and may have a central opening I6 therethrough, as -well as a plurality of spaced openings I'I located inwardlyof lthe outer edge of the slab. The purposes of these openings will be later pointed-out. The rubber covering I2 extends around -and substantially completely encases/the insulating material or slab II. As will be explained hereinaiter, the rubber covering is molded vand vulcanized vin place around the insulating material andthe top and bottom walls or portions I`2a `and I2b ofthe rubber covering, as well as the rim I4 and ilangev I5, constitute integral portions of 'a unitary body of rubber'. The rubber covering I2 also includes integral stems I'Ia which extend into or throughthe openings Il of the insulating material and connect the top and bottom portions I2a and I2b. These integral stems serve to connect the top and bottom portions I^2a and I2b of the rubber covering with the insulating material and with each other so as to strengthen they lid and lhold the rubber from blistering or bulging away from the insulating material.v

Another feature of our refrigerator lid I0 is the provision of 'a layer I9 of fabric 0r duck on its top and bottom faces. `This fabric layer-extends over substantially the entire top and bottom faces of the lid and is embedded in the surfaceof the rubber covering I2 `soas to become integrally united therewithandso vthat the rubber` will permeatethe .fabric and provide smooth surfaces on the topy and bottom lof-.the lid. l,Thisfabric layer reinforces and strengthens the lid and also In Fig. 4 we show molding apparatus Whicli' l may be used in producing composite articles by y our method, such as the above-described refrigerator lid I0. This apparatus comprises al Ifld 2| of a form to be received between a' pair of co7- operating upper and lower platens 22 and 23,

which may be a pair of steam-heated platens 'of' a conventional vulcanizing press.

The mold 2| comprises upper and lower sections 24 and 25 and an intermediate rin'g Section' 2 6.n The. upper and-lower-,sec-tions havefrecesses or depressions formed in'tlieirfadfjacent faces'. amd-when these sections are inassembled relation with.. the ring.' sectionv 21S-therebetween, as Y shown in 4, they denne a worliingl chamber ormold cavity 21. The mold sections maybejretained in the desired .rregisteringL relation blyV providing the same with suitable dowel pins 28 andl d owel pin openings. 28. Thel intermediate mold section- 26 be aJ single part or member,.or preferably,y as

here shown,A may" be a laminated structure com-I posed. of a plurality of.` layers 25a held togethery by means of screws 266i Theupperand lower'mold sections may be providedlwith gaskets 24a and 25a which engage the intermediate section 26 when. the mold is inV assembled!` conditionr forma seal ai'ound'th'e outer edge oflthev mold cavifylzl. i

musing the' mold 2|' to produce the composite rei/rigerator lid lugwe' place the' insulating ma-` terial orzsiab H inthe mold cavity between sheets of uncured rubber" stock and with the layersA of fabricor duck' fs 'overlyingv the sheets of rubber stock; that is' to say, extending between the rubber stoel: and the top and bottom 'face'soffthe nrold cavity. The thickness of thisassenrbly of insulating materiali, sheets ofl riibb'erV stock, and' layers of' fabric should be? substantially equal'zto, patrioti matriau-yin excess or, the closed' height ofthe moidrcavi'ty 2T so that the mold-can lie conveniently closed esiliv this assembly without subi'ectmg the saine1 to undue 'pressure which would compact"- th'e insulating` material and 'rei-i der the'k saine more cleiiseanu l'ess resistant to 'the' transfer of heat or cold. n Thelmold: is maintained closed by the pressure cifthe/coop; erating platensi 22 and 23" ofwth vulcanizing press, and heat for curing and molding the rub'dv ber is supplied to the moldby the pla-tensa Duri-I ing the curing or vulcanizing operation the rub ber stock is molded. aroundthe insulating material or slab Illy to substantially orcompletely encase.v the same. in a unitary bod-y of vulcanized rubber, vas shown in Figs. Land 2. During this operation the fabric layers L9 become embedded inthe upper* and Tower faces `ofthe rubber coveri'ng;

When the rubber news around the insulating' material, it' will. be understood that this material' becomes trapped' or. encased in the rubber. The insulating 'material' invariably contains air and some moisture, and" in some instances, may also contain substances which will emit gaswhen heated: i The Avulcani'zing heatexpands theN air andfconverts the moisture into steam, andthe resulting gaseous medium creates a pressure Within the composite article being formed. The pressure of the gaseous medium acts outwardly against the rubber and serves the useful purpose of pressing the same against the faces of the mold cavity and thus assists in molding the rubber without having' the insulating material subjected to undue pressure' by themold sections which, as explained above, might decrease its insulating properties.

-If the mold were to be opened while the inter-nall pressure in the article is still active, the article might be blown apart or might be darna'gge'd by bulging or blistering of the rubber covring' f2. Tov` prevent this and to be able to more or'less control the pressure within the article being formed, We provide the mold cavity with a hollow pin or needle 30 which extends into the insulating material and has a passage 3l leading to" an external point of the mold so that the gaseous medium trapped in the article can be vented to atmosphere or withdrawn by suction.

The pin 38 may be mounted on the lower mold section 25' so as to extend across the mold cavity 21 and may have a pilot portion 30a which is snugly received and guided in an opening 32 of the upper mold section. The pin 32] may be connectedl with the lower mold section in any appropriate Way as by providing the pin with an enlarged base 33 which is recessed into' this mold section. We prefer to locate the pin 3D at a central point'of the moldso that the opening I6 which is providedv in the insulating body to receive this pin will. be appropriately located so that it can be` used for the handle-retaining screw I 3a. The passage 3i Aof the pin 30 may communicate with the moldy cavity 21 at a plu rality of points, and this'r may be accomplished by providing the pin with axially spaced periph eral grooves 34 which, are connected with ythe passage 3l by radial openings 35.*` The lower mold section 25 may have a relatively small pase sage or tube36 therein which forms an extension ofthe passage 3l of the pin and has a terminal portion 36a which may open toatmosphere or may be connected with suitable suction appara- We have found-thel above-described molding appara-tus to operate satisfactorily andto produce refrigeratorl lids of a desired uniforml high quality when the tube or passage 36I is left *open to atmosphere during the rst portion of the molding and Vulcanizing operation an'd is'corinected to the suction apparatus eith'er' during the latter portion of the molding and vvulcanizing operation and is connected to the suction apparatus eitherA during the latter portionl of the molding and vulcaniz'ing operation i or just prior to the opening o'f the mold '21. By leaving the passage 36 open to atmosphere during the rst portion of the molding and vulcaniz'ing' operation we nd that the gaseous medium trapped in the insulating material Hf' creates some pressure within the'artic'leb'eing formed' and', as explained above, this is desir'- able for pressing the rubber against the faces of theV mold" cavity to give the article' an accurate shape and smooth' iinish. Near the end ofL the moldingand vul'canizing operation or just prior to the opening' of the mold, we in'dit. desirable to connect the passage 35 to the' suction appar'atus so as to Withdraw the gaseous medium from within the articlevand thus reduce the iriternal' pressure to a point which will. permit the' mold to be opened without damage to the product.

Since the mold cavity is sealed around its edge, there will be some air trapped in the cavity at the start of the molding and vulcanizing operation. It is desirable to permit or assist the escape of this air from the mold cavity so that it will not form bubbles or pockets between the rubber and mold faces and result in irregularities in the molded surface of the article being produced. For this purpose we provide a plurality of spaced vent openings 31 which extend through the uper and lower mold members and connect the cavity with atmosphere. We have stated above that the fabric layers i9 serve a useful purpose during the molding and vulcanizing operation. This useful purpose is to conduct the trapped air along the surface ofthe rubber to the vent openings 31, from which it can escape freely to atmosphere. In accomplishing this purpose the fabric or duck acts more or less in the nature of a wick or porous medium through or along which the trapped air can travel to the vent openings 31.

From the foregoing description and the accompanying drawing, it will now be understood that we have not only provided a novel construction for a composite refrigerator lid or like article, but have also provided a method and apparatus for producing such articles.

While We have illustrated and described our improved article, method, and apparatus in a more or less detailed manner, it will be understood, of course, that we do not wish to be limited to the precise structural features herein clisclosed, but regard our invention as including such changes and modifications as do not constitute a departure from the spirit of the invention and the scope of the appended claims.

Having thus described our invention, we claim:

l. A refrigerator lid comprising a hollow body of molded rubber having spaced top and bottom walls, a filler of insulating material in the form of a substantially flat slab substantially filling the cavity in said hollow body and having openings therethrough at spaced points inside its outer edge, rubber stems connecting said top and bottom walls and extending through said openings of said iiller, and a layer of fabric extending over the outer faces of said top and bottom walls, said fabric being integrally united with and permeated -by said rubber.

2. A refrigerator lid comprising a disk-shaped hollow body of molded soft rubber having spaced substantially fiat top and bottom walls, a ller comprising a substantially flat slab of insulating material substantially filling ,the cavity in said hollow body and having an opening therethrough substantially centrally thereof and other openings therethrough at spaced points between its central opening and its outer edge, said top and.

bottom walls having openings aligned substantially with the central opening of said ller, integral rubber stems connecting said top and bottom walls and extending through said other openings, a layer of fabric extending over the outer faces of said top and bottom walls and being intgerally united with and permeated .by said rubber, and a knob attached to the lid by a fastening member extending through and substantially lling said aligned openings.

JOHN F. MCWI-IORTER. MARION W. HUMPHREYS. 

